Lupus band test in uninvolved oral mucosa in systemic lupus erythematosus

In 42 patients with systemic lupus erythematosus, clinically normal oral mucosa was investigated with direct immunofluorescence technique for the presence of immunoglobulins G, A and M and complement factor C3 in the mucosal basement membrane zone (the lupus band test, LBT). Punch biopsies were performed in the posterior part of the hard palate (n = 39) or the lower labial mucosa (n = 3). The immunopathological observations were compared with clinical and serological data. The LBT was positive for IgM in 45% of the patients and trace amounts of IgM were found in another 19%. In 7 cases (17%) either IgG, IgA or C3 were found in addition to IgM and these patients all had a severe form of the disease, while the presence of IgM only was not correlated to clinical parameters.

The minor salivary gland proteome in Sjögren's syndrome

OBJECTIVE

To identify the global protein expression (the proteome) in the minor salivary glands from primary Sjögren's syndrome (pSS) patients and non-SS controls.

MATERIALS AND METHODS

Minor labial salivary glands were obtained from six pSS patients and from six age-matched non-SS controls, lysed in SDS buffer and pooled into two groups, respectively. The lysates were analysed by liquid chromatography electrospray ionization combined with tandem mass spectrometry. Also, the proteins were separated by two-dimensional polyacrylamide gel electrophoresis and protein spots were subjected to mass spectrometry.

RESULTS

Heat shock proteins, mucins, carbonic anhydrases, enolase, vimentin and cyclophilin B were among the proteins identified. The differences in the proteomes of minor salivary glands from pSS patients and non-SS controls were mainly related to ribosomal proteins, immunity and stress. Alpha-defensin-1 and calmodulin were among six proteins exclusively identified in pSS patients.

CONCLUSION

We have identified several minor salivary gland proteins that may have implications for clarifying the SS pathophysiology. This experiment adds to the knowledge of proteins produced in salivary glands in health and disease, and may form the basis of further studies on biomarkers of prognostic and diagnostic value.

Aspects of B-cell non-Hodgkin's lymphoma development: a transition from immune-reactivity to malignancy

The development of B-cell lymphomas is an intricate interplay among various pathogenic factors, leading to a multi-step process, encompassing various stages of B-cell maturation. Besides genetic abnormalities, a variety of environmental and microbial factors, as well as disproportional immune-regulatory processes lead to the malignant transformation. Yet, little is known about the exact chain of events, which lead from the physiological polyclonal B-cell activation as a response to exogenous antigens through oligoclonality to a monoclonal, uncontrolled, malignant B-cell proliferation. The aim of the present review was to summarize the potential harmful steps in the development of B-cell lymphomas, according to conventional and novel theories, and to depict therapeutic regimens presently in use as well as to envision future drug developments, beneficial in the battle against this lymphoid malignancy.

Anti-CD20 treatment in primary Sjögren's syndrome

We performed a search for publications on rituximab (Rtx) in the treatment of primary Sjögren's syndrome (pSS), and assessed the reports for the efficacy of the drug on complaints like sicca symptoms, systemic manifestations and pSS associated lymphoma. We also reviewed the effects on laboratory parameters and potential adverse effects. From the published literature there is little evidence supporting Rtx to have an effect on sicca symptoms, and there is particularly lack of objective improvements in measures of oral and ocular dryness. Systemic manifestations such as fatigue, synovitis, arthralgia, cryoglobulinaemia-related vasculitis, neurological, renal and pulmonary involvement all seem to react favourably to Rtx treatment. The effect on pSS associated non-Hodgkin's lymphoma is also beneficial. Rheumatoid factor concentration is decreasing during Rtx treatment. The levels of anti-SSA and -SSB antibodies are, however, unaltered according to the majority of the studies. The most common complications to Rtx treatment are mild and transient infusion related reactions. Delayed moderate-to-severe reactions are less common, and occur mostly in patients who develop human anti-chimeric antibodies. In conclusion, Rtx is a promising treatment option for severe pSS with systemic complications, but more data from randomized controlled trials are warranted before conclusions on the drug's role can be made with more accuracy.

Inhibition of experimental Sjögren's syndrome through immunization with HSP60 and its peptide amino acids 437-460

OBJECTIVE

To investigate a potential immunomodulatory effect of the 60-kd heat-shock protein (Hsp60) on experimental spontaneous Sjögren's syndrome (SS).

METHODS

Seven-week-old nonobese diabetic (NOD) mice were immunized with eukaryotic Hsp60 or an Hsp60-derived peptide (amino acid residue [aa] 437-460). At 21 weeks of age, nondiabetic mice were investigated for salivary gland inflammation, exocrine function, and extraglandular disease manifestations. In addition, biomarker profiles comprising 87 analytes in serum and 75 in saliva were analyzed.

RESULTS

In mice immunized with Hsp60 and aa 437-460, SS-related histopathologic features were significantly reduced compared with NOD controls. In addition, 50% of Hsp60-injected mice and 33% of aa 437-460-injected mice retained normal exocrine function. Both treatments induced similar changes in biomarker profiles. Notably, levels of circulating interferon-gamma-inducible 10-kd protein (IP-10) and eotaxin were decreased significantly after treatment. Anti-type 3 muscarinic acetylcholine receptor (anti-M3R) IgG1, interleukin-10, and leptin discriminated best between the different treatment groups. Successful prevention of hyposalivation was accompanied by quantitative alterations in 36 biomarkers, of which 19 mediators of inflammation declined to levels comparable with those found in BALB/c mice. Low secreted vascular endothelial growth factor A was the most accurate predictor of successful prevention of hyposalivation. Low salivary granulocyte chemotactic protein 2 was identified as the best predictor of normal secretory function across the strains.

CONCLUSION

Immunization with Hsp60 and its peptide aa 437-460 led to inhibition of SS in NOD mice. Comprehensive analyses revealed specific biomarker signatures capable of predicting treatment group and treatment outcome. Molecules involved in inflammatory chemotaxis, neovascularization, and regulatory pathways caused the differences displayed by the biomarker profiles.

Altered fractalkine cleavage results in an organ-specific 17 kDa fractalkine fragment in salivary glands of NOD mice

Sjögren's syndrome is a rheumatic disease in which the salivary and lacrimal glands are the principal targets of a pathological autoimmune reaction. Previous studies in mice indicated that delayed organogenesis and aberrant cell physiology followed by an increase in acinar cell apoptosis precede chronic focal inflammation in the salivary glands and the manifestation of impaired exocrine gland secretion. In a recent study by Wildenberg and colleagues, the authors report aberrant proteolytic activity in the salivary glands of non-obese diabetic mice and the generation of a unique organ-specific 17 kDa fragment of the chemokine and adhesion molecule fractalkine.

Germinal Centres in Primary Sjögren's Syndrome Indicate a Certain Clinical Immunological Phenotype

Ectopic germinal centers (GCs) can be detected in the salivary glands of approximately 1/5 of patients with Sjögren's syndrome (SS) and appear in both primary and secondary SS. Previously, ectopic GC have been associated with increased local autoantibody production. The aim of this study was to determine whether GC in primary Sjögren's syndrome (pSS) defines a distinct seroimmunological phenotype. Retrospectively, a material of 130 haematoxylin and eosin‐stained paraffin‐embedded tissue sections of minor salivary gland tissue from patients with pSS was morphologically screened for the presence of ectopic GC. GC‐like lesions were detected in 33/130 (25%) of the pSS patients. Seventy‐two pSS patients lacking these structures (GC‐) were randomly selected for comparison. Focus score was significantly increased in the GC⁺ patients compared to the GC^– patients (P = 0.035). In the GC⁺ group, 54.5% of the patients presented with anti‐Ro/SSA compared to 43.7% in the GC^– group. Anti‐La/SSB was detected in 31.3% of the GC⁺ patients compared to 25.7% of the GC^– patients. Sixty‐one percentage of GC⁺ patients presented with increased levels of IgG, a nonsignificant difference when compared to 39.4% in the GC^– patients (P = 0.089). Levels of RF, ANA, ENA, IgM and IgA were similar in both patient groups, as were ESR and CRP. In conclusion, patients with ectopic GC have a higher focus score and more often present with autoantibodies and increased levels of IgG compared to pSS patients with regular focal infiltration (GC^–). Our findings may indicate a certain seroimmunological phenotype and warrant for further prospective studies.

The complex role of vitamin D in autoimmune diseases

Vitamin D, besides having well-known control functions of calcium and phosphorus metabolism, bone formation and mineralization, also has a role in the maintenance of immune-homeostasis. The immune-regulatory role of vitamin D affects both the innate and adaptive immune system contributing to the immune-tolerance of self-structures. Impaired vitamin D supply/regulation, amongst other factors, leads to the development of autoimmune processes in animal models of various autoimmune diseases. The administration of vitamin D in these animals leads to improvement of immune-mediated symptoms. Moreover, in human autoimmune diseases, such as multiple sclerosis, or rheumatoid arthritis the pathogenic role of vitamin D has been described. The review aims at describing the complex immune-regulatory role of vitamin D from the cellular level through autoimmune animal models and depicting the known contribution of vitamin D in the pathogenesis of human autoimmune diseases.

Automatic fitting procedures for EPR spectra of disordered systems: matrix diagonalization and perturbation methods applied to fluorocarbon radicals

Two types of automatic fitting procedures for EPR spectra of disordered systems have been developed, one based on matrix diagonalization of a general spin Hamiltonian, the other on 2nd order perturbation theory. The first program is based on a previous Fortran code complemented with a newly written interface in Java to provide user-friendly in and output. The second is intended for the special case of free radicals with several relatively weakly interacting nuclei, in which case the general method becomes slow. A least squares' fitting procedure utilizing analytical or numerical derivatives of the theoretically calculated spectrum with respect to the g- and hyperfine structure (hfs) tensors was used to refine those parameters in both cases. 'Rigid limit' ESR spectra from radicals in organic matrices and in polymers, previously studied experimentally at low temperature, were analyzed by both methods. Fluorocarbon anion radicals could be simulated, quite accurately with the exact method, whereas automatic fitting on, e.g. the c-C(4)F(8)(-) anion radical is only feasible with the 2nd order approximative treatment. Initial values for the (19)F hfs tensors estimated by DFT calculations were quite close to the final. For neutral radicals of the type XCF(2)CF(2)* the refinement of the hfs tensors by the exact method worked better than the approximate. The reasons are discussed. The ability of the fitting procedures to recover the correct magnetic parameters of disordered systems was investigated by fittings to synthetic spectra with known hfs tensors. The exact and the approximate methods are concluded to be complementary, one being general, but limited to relatively small systems, the other being a special treatment, suited for S=1/2 systems with several moderately large hfs.

The influence of the NOD Nss1/Idd5 loci on sialadenitis and gene expression in salivary glands of congenic mice

The nonobese diabetic (NOD) Nss1 and Idd5 loci have been associated with sialadenitis development in mice. In this study the NOD Nss1 and Idd5 loci were backcrossed onto the healthy control strain B10.Q by using the speed congenic breeding strategy, resulting in three congenic strains: B10.Q.Nss1, B10.Q.Nss1/Idd5 heterozygous and B10.Q.Nss1/Idd5 homozygous. We investigated the effects of the Nss1 and Idd5 loci on sialadenitis and gene expression in NOD congenic mice. One submandibular salivary gland from each mouse was used for histological analysis of sialadenitis, whereas the contralateral salivary gland was used for gene expression profiling with the Applied Biosystems Mouse Genome Survey chip v.1.0. The results were validated using quantitative reverse transcriptase PCR. The NOD Nss1 and Idd5 loci had clear influence on the onset and progression of sialadenitis in congenic mice. Double congenic mice exhibited the most severe phenotype. We successfully identified several genes that are located in the NOD congenic regions to be differentially expressed between the congenic strains and the control strain. Several of these were found to be co-regulated, such as Stat1, complement component C1q genes and Tlr12. Also, a vast contingency of interferon-regulated genes (such as Ltb, Irf7 and Irf8) and cytokine and chemokine genes (such as Ccr7 and Ccl19) were differentially expressed between the congenic strains and the control strain. Over-representation of inflammatory signalling pathways was observed among the differentially expressed genes. We have found that the introgression of the NOD loci Nss1 and Idd5 on a healthy background caused sialadenitis in NOD congenic mouse strains, and we propose that genes within these loci are important factors in the pathogenesis. Furthermore, gene expression profiling has revealed several differentially expressed genes within and outside the NOD loci that are similar to genes found to be differentially expressed in patients with Sjögren's syndrome, and as such are interesting candidates for investigation to enhance our understanding of disease mechanisms and to develop future therapies.

Biomarker profiles in serum and saliva of experimental Sjögren's syndrome: associations with specific autoimmune manifestations

INTRODUCTION

Sjögren's syndrome (SS) is a systemic autoimmune disease that mainly targets the exocrine glands. The aim of this study was to investigate the involvement of 87 proteins measured in serum and 75 proteins analyzed in saliva in spontaneous experimental SS. In addition, we intended to compute a model of the immunological situation representing the overt disease stage of SS.

METHODS

Nondiabetic, nonobese diabetic (NOD) mice aged 21 weeks were evaluated for salivary gland function, salivary gland inflammation and extraglandular disease manifestations. The analytes, comprising chemokines, cytokines, growth factors, autoantibodies and other biomarkers, were quantified using multi-analyte profile technology and fluorescence-activated cell sorting. Age-matched and sex-matched Balb/c mice served as a reference.

RESULTS

We found NOD mice to exhibit impaired salivary flow, glandular inflammation and increased secretory SSB (anti-La) levels. Thirty-eight biomarkers in serum and 34 in saliva obtained from NOD mice were significantly different from those in Balb/c mice. Eighteen biomarkers in serum and three chemokines measured in saliva could predict strain membership with 80% to 100% accuracy. Factor analyses identified principal components mostly correlating with one clinical aspect of SS and having distinct associations with components extracted from other families of proteins.

CONCLUSION

Autoimmune manifestations of SS are greatly independent and associated with various immunological processes. However, CD40, CD40 ligand, IL-18, granulocyte chemotactic protein-2 and anti-muscarinic M3 receptor IgG3 may connect the different aspects of SS. Processes related to the adaptive immune system appear to promote SS with a strong involvement of T-helper-2 related proteins in hyposalivation. This approach further established saliva as an attractive biofluid for biomarker analyses in SS and provides a basis for the comparison and selection of potential drug targets and diagnostic markers.

Animal models of Sjögren's syndrome

Sjögren's syndrome is an autoimmune, chronic inflammatory disease characterized by focal mononuclear cell infiltration of exocrine tissues, accompanied by loss of secretory function. The pathogenesis of autoimmune diseases is complex and, therefore, difficult to study in vitro. As of today, the role of initiating factors remains obscure, clinical symptoms develop late, and there are no tests for early diagnosis of SS. Hence, the disease is difficult to detect and treat. Animal models may provide insights into the identification of target antigens, narrowing the relevant pathological immune mechanisms, and to study the evolution of tissue pathology. This review summarizes current knowledge on murine strains, both spontaneous and induced models, used to study Sjögren's syndrome. Special attention is paid to the characteristics of different strains regarding their properties to mimic specific aspects or stages of the disease.

Sjögren's syndrome--a plethora of clinical and immunological phenotypes with a complex genetic background

Primary Sjögren's syndrome is a complex autoimmune disorder, considered to represent an ideal disease with which to study the mechanisms underlying autoimmunity because its manifestations are both organ specific and systemic in nature. The characteristic histologic finding in target organs is a progressive focal infiltration of mononuclear lymphoid cells, replacing glandular epithelium (lymphoepithelial lesion). This involvement has been re-emphasized in the 2002 revised EU criteria for Sjögren's syndrome. Moreover, ectopic secondary lymphoid follicles in Sjögren's syndrome contain all elements of relevance for driving an autoimmune response. A number of cytokines and chemokines are involved and particularly B cell activating factor seems to direct the lifespan of infiltrating B cells by enhancing their proliferation and maturation. The recent discovery of clinical benefit after B cell depletion also highlights the pivotal role of B cells in Sjögren's syndrome. A major challenge in Sjögren's syndrome will be to stratify the disease process including genetic and environmental triggers. Identification of novel genetic and molecular markers may lead to the development of better diagnostic and prognostic tools in Sjögren's syndrome including its systemic complications. This minor review will cover the current knowledge on classification, pathogenesis, multiplex findings, potential candidate genes, gene profiling results, and novel therapy approaches. New hypotheses behind the complexity of Sjögren's syndrome are expected to follow.

Serological implications of germinal center-like structures in primary Sjögren's syndrome

OBJECTIVE

To determine serological implications of germinal center (GC)-like structures in primary Sjögren's syndrome (pSS).

METHODS

Retrospectively, minor salivary gland biopsies (n = 269) with focal lymphoid aggregates corresponding to focus score > 1 were evaluated for the presence of GC-like morphology. Relevant clinical information was obtained from medical records.

RESULTS

Of 269 patients, 169 fulfilled the American-European criteria for pSS. GC-like features were observed in 47/169 (28%) biopsies. In the majority of cases, GC-like lesions were confirmed by CD21-positive follicular dendritic cell networks. Mean inflammatory focus score was significantly higher in GC-positive compared to GC-negative samples (p < 0.001). GC-positive patients had lower mean salivary secretion (p < 0.001) and a higher frequency of patients with unstimulated salivary secretion < or = 1.5 ml/15 min (p < 0.01). In addition, elevated titers of rheumatoid factor, serum anti-Ro/SSA and anti-La/SSB (p < 0.05), and IgG levels > or = 15.3 g/l (p < 0.05) were more common in GC-positive compared to GC-negative. Enlarged salivary glands were observed in 46/163 (28%) patients, but could not be linked to either presence or absence of GC-like features.

CONCLUSION

Inflammatory infiltrates with GC-like morphology were observed in 28% of the investigated patients with pSS, and was particularly noted in patients with higher focus score. The observed serological aberrations in patients with ectopic GC-like structures in the minor salivary glands warrant further prospective studies.